The class of drugs used for migraine prevention has been linked to an increased risk of spontaneous abortion in the first twenty weeks of pregnancy, which was approximately 40%. This study was published in the journal JAMA Neurology and was based on an analysis of data from 7,579 pregnancies.
The research examined monoclonal antibodies that block CGRP—a molecule involved in both migraine attacks and important processes of pregnancy. Although the results do not prove that these medications cause abortions, they raise questions about their safety during gestation.
Migraines are not always treatable with standard analgesics. In 2018, a class of injectable drugs emerged, offering an alternative for patients who do not improve after taking oral medications such as triptans and ergotamine.
These drugs block CGRP, which stands for calcitonin gene-related peptide. This molecule is involved in migraine crises but also affects blood flow regulation, embryo implantation, and placenta development. Involvement in such diverse processes prompted researchers to investigate a possible link between the treatment and complications during pregnancy.
The study, led by epidemiologist Annie Barrard from St. Justin University Hospital in Canada, utilized private health insurance records from the United States collected between 2018 and 2021.
The analysis covered women diagnosed with a migraine attack or those who took prescription triptans or ergotamine-based drugs within six months prior to their last menstrual period. Researchers evaluated four monoclonal antibodies: Erenumab, Fremanezumab, Galcanezumab, and Eptinezumab. The data also allowed for a comparison with data concerning propranolol, another drug used for migraine prevention.
It was found that exposure to monoclonal antibodies during the first twenty weeks of pregnancy was associated with an approximately 40% higher risk of spontaneous abortion. No such association was observed when using propranolol.
However, researchers emphasize that this study is observational and does not allow for the establishment of a causal relationship. Among the limitations noted is that the severity of the migraine itself may be related to the observed risk, so this link cannot be attributed solely to the medications.
The authors call for new studies to assess the safety of these medications during pregnancy, including their potential impact on fetal development and long-term child health. According to the authors, the increasing use of these treatments for migraine prevention in reproductive-age individuals makes this investigation particularly relevant.
Until further evidence emerges, it is recommended to discuss risks and alternatives with a doctor before making any changes to treatment. For those planning pregnancy, these results underscore the need to discuss medication safety, but they do not allow the conclusion that monoclonal antibodies cause spontaneous abortions.